Basic dye-bath and method for dyeing acrylic fibers therewith

ABSTRACT

Non-aqueous dye-baths for dyeing acrylic fibers comprising basic dye dissolved in a mixture of (a) an aromatic ketone having the formula   WHEREIN Y is hydrogen, halogen, or alkyl of 1-4 carbon atoms and R is alkyl of 1-4 carbon atoms, and (b) a dye-dissolving agent such as acetic acid, formic acid, thio-diethylene glycol, diethylene glycol, and ethylene glycol. Acrylic fibers are dyed by treating them with such a bath and then fixing the dye by heat treatment, such as by steam.

Unite Sttes atent n 1 Abeta BEST AVAILAB COW 11 3,891,390 [45] June 24, 1975 I BASIC DYE-BATH AND METHOD FOR DYEING ACRYLIC FIBERS THEREWITH [75] Inventor:

[73] Assignee: American Cyanamid Company,

Stamford, Conn.

22 Filed: Apr. 14, 1971 21 Appl.No.: 134,056

Sadaharu Abeta, Toyonaka, Japan OTHER PUBLICATIONS J. E. Lynn ct al., Advances in Textile Processing, Vol. 1, 1961, page 360.

Primary Examiner-Thomas J. Herbert, Jr. Attorney, Agent, or FirmWilliam J van Loo [57] ABSTRACT Non-aqueous dye-baths for dyeing acrylic fibers comprising basic dye dissolved in a mixture of (a) an aromatic ketone having the formula C-OB wherein Y is hydrogen, halogen, or alkyl of 1-4 carbon atoms and R is alkyl of 1-4 carbon atoms, and (b) a dye-dissolving agent such as acetic acid, formic acid, thio-diethylene glycol, diethylene glycol, and ethylene glycol. Acrylic fibers are dyed by treating them with such a bath and then fixing the dye by heat treatment, such as by steam.

5 Claims, N0 Drawings BASIC DYE-BATH AND METHOD FOR DYEING ACRYLIC FIBERS THEREWITH The present invention relates to a dye-bath of a basic dyestuff and to a dyeing method for acrylic fibers using such dye-bath. More particularly, the present invention in its product aspect relates to a basic dyestuff dissolved in a combination of an aromatic ketone and a dye-dissolving agent. More particularly, the present invention in its process aspect relates to treating acrylic fiber with the dye-bath and subsequenting subject the treated fibers to heat treatment.

The dyeability of acrylic fibers is determined to some extent by the nature of the polymer of which they are formed and by the nature of the process by which they are obtained. ln spite of inherent differences in dyeability among acrylic fibers depending on their origin, in most instances basic dyestuffs can be used to dye acrylic fibers with fast shades.

The conventional method of dyeing acrylic fibers with basic dyestuffs involves an exhaustion procedure. In such procedure, a given weight of fibers is placed in a dye-bath containing the requisite weight of dyestuff and alkali as well as any levelling agent contemplated. The dye-bath is then gradually heated to the dyeing temperature and maintained at the dyeing temperature until the acceptable degree of exhaustion has been achieved. The dye-bath is then cooled and discharged, after which the fibers are washed, rinsed, and dried. Although the procedure produces fast dyeings, the extensive time required, generally several hours, is a readily recognized deficiency. Discharge of the spent dye-bath, with its residual content of dyestuff, alkali, and levelling agent, can cause pollution problems in drainage streams Additionally, the requirement for batch-wise operation is a serious deficiency.

Some attempts have been made to increase dyeing rates by use of higher dyeing temperatures in combination with increased pressure. Additional expedients involve modification of the polymer molecule to provide dye sites and of new dye classes specific for acrylic fibers. Although some benefits are realized by the various expedients employed, the time required to complete the dyeing procedure remains unduly long. In addition, provision for dyeing of endless fiber lengths in a continuous procedure is not available. The problem of pollution of discharge streams is not resolved by any of the expedients suggested. Accordingly, there continues to exist the need for dye-baths and dyeing procedures that eliminate the above-described deficiencies.

In accordance with the product aspect of the present invention, there is provided a dye-bath consisting essentially of: (a) a basic dyestuff; (b) an aromatic ketone of the formula wherein Y is selected from the group consisting of hydrogen, halogen, and alkyl of 1-4 carbon atoms and R is alkyl of 1-4 carbon atoms; and (c) a dyedissolving agent selected from the group consisting of acetic acid, formic acid, thio-diethylene glycol, diethylene glycol, and ethylene glycol.

In accordance with the process aspect of the present invention, there is provided a process for dyeing acrylic fibers which comprises treating said fibers with the dyebath described above and thereafter subjecting the treated fibers to heat treatment.

The present invention provides a unique dye-bath of basic dyestuff useful for dyeing acrylic fibers. The dyebath enables the brilliance of shade and great tinctorial value of the basic dyestuff class to be used to advantage in dyeing acrylic fibers. The dyeings obtained exhibit good lightfastness and resistance to humidity. The dyeing process of the present invention is effectively performed on all types of acrylic fibers in a minimum of time in a continuous process. The process does not require excessive temperatures and pressures, polymer modification, special dyestuff class, and, at the same time, eliminates pollution problems associated with discharge of spent dye-bath.

The dyestuff class used in the present invention, as has been indicated, is that of basic dyestuffs. This class is generally described as being used for dyeing in alkaline solution. Such dyes generally contain a pentavalent nitrogen atom, usually, but not necessarily, in the triphenylmethane structure wherein R is an alkyl or aryl group, and X is the anion ofa mineral or organic acid. The various properties and identity of members of this well-known dyestuff class can be obtained from The Colour Index, published jointly by Society of Dyers and Colourists, Yorkshire, England and American Association of Textile Chemists and Colorists, Lowell, Mass. Any of this dyestuff class may be employed in the present process so long as it is soluble in a dye-dissolving agent miscible with the selected aromatic ketone. Certain fluorescent compounds, although essentially non-coloring, are included in this class since they have the effect of producing increased whiteness of the fibers. Such compounds are otherwise identified as brighteners.

The amount of dyestuff used in preparing the dyebath will vary widely depending upon the specific dyestuff employed and the particular shade of color desired. One or more basic dyestuffs may be employed to produce particular shades. The amount of dyestuff will also depend upon the method by which application is effected and the amount of dye-bath deposited upon the fibers. The amount of dyestuff used is determined by the color shade desired and is consistent based on the weight of fibers with conventional usages.

Conventionally known dye-dissolving agents are employed in a quantity sufficient to dissolve the basic dyestuff. Such dye-dissolving agents include acetic acid, formic acid, thio-diethylene glycol, diethylene glycol, ethylene glycol, and the like. The dye-dissolving agents must also be miscible with the aromatic ketone employed. The dye-dissolving agent will constitute a minor portion of the total dye-bath composition, usually not more than about 25 percent by weight, preferably percent by weight, based on the weight of aromatic ketone.

The aromatic ketone is of the structure previously given and includes such compounds as 0-, m-, and pmethyl acetophenone, m-ethyl acetophenone, mchloroacetophenone and other acetophenone derivatives; 0-, m-, and p-methyl phenylethyl ketone, methylphenyl ethyl ketone, and other phenyl ethyl ketone derivatives; and mixtures of such compounds. The aromatic ketone will constitute the major portion of the dye-bath and usage will be dependent upon the amount of dyestuff and dye-dissolving agent employed as well as upon the shade of color desired. Once the particular treating procedure is established, the amount of dyestuff, dye-dissolving agent, and aromatic ketone naturally follow from a knowledge of the particular dye shade desired.

In carrying out the dyeing process of the present invention, a dye-bath, as described above, is prepared. The various ingredients may be added in any order desired so long as a homogeneous solution is obtained. lt is generally preferred to dissolve the dyestuff in the dyedissolving agent first and then add the aromatic ketone to the dye solution.

The fibers that are employed in the process of the present invention are those which fall in the class known as acrylic fibers. An acrylic fiber, as defined by the Federal Trade Commission, Rules and Regulations under the Textile Fiber Products Identification Act, Effective Mar. 3, 1960, page 4, is a manufactured one in which the fiber-forming substance is any long-chain synthetic polymer composed of at least 85% by weight of acrylonitrile units A modacrylic fiber is one composed of less than 85% but at least 35% by weight of acrylonitrile units. Preferred fibers are those which contain at least 70 percent acrylonitrile units by weight. Dyeing may be carried out with such fibers in any form, but it is generally preferred to treat fibers in fabric form.

The method of treatment of fibers may be any of conventional methods, such as by dipping, padding, spraying, and the like. The amount of dye-bath deposited on the fibers is that necessary to produce the desired color shade. The amount of dye-bath deposited on the fibers may be controlled by squeeze-rolls, centrifugation, and similar devices or by controk of the amount sprayed. Treatment is normally carried out in a manner whereby uniform distribution of dyestuff is obtained. Generally, the fibers, in the form of a fabric, are dipped into the dyebath and then squeezed between pad rolls to control the pickup of dyebath. The fibers are then subjected to heat treatment to effect fixation of the dyestuff. Heat treatment may be with saturated steam or dry air. Saturated steam at 100C. for 2 minutes produces satisfactory results as does dry air at 150C. for 1 minute. A variety of additional heat treatments may be employed.

The process may be carried out in continuous manner by employing a padmangle and heating chamber in tandem relationship. Fabric, for example, may be entered into the dyebath, fed to the pad-mangle to control dye pickup and immediately passed into a heating chamber to fix the dyestuff. The dye-bath may be replenished as necessary.

The invention is illustrated by the examples which follow, in which the parts are by weight.

EXAMPLE 1 A dye-bath was prepared by dissolving 2 parts of a dyestuff of the following formula:

in a mixture of 100 parts of m-methyl acetophenone and 10 parts of glacial acetic acid.

A fabric made from an acrylic fiber in which the polymer comprises 8 percent methyl acrylate and 92 percent acrylonitrile, by weight, was dipped into the dye-bath at 30C. and squeezed with a pad mangle so as to effect a wet pickup of percent of dyebath based on the weight of the fabric. The fabric was then subjected to saturated steam at C. for 2 minutes. There was obtained a red fabric which exhibited excellent fastness when subjected to sunlight and humidity.

EXAMPLE 2 A dye-bath was prepared by dissolving 3 parts of a dyestuff of the following formula:

in a mixture of 100 parts of phenyl ethyl ketone and 10 parts of diethyleen glycol. A fabric of acrylic fiber in which the polymer comprises 9.5 percent methyl acrylate and 90.5 percent acrylonitrile, by weight, was dipped into the dye-bath at 30C., squeezed with a padmangle to effect a wet pickup of percent of dyebath based on the weight of fabric. The fabric was then subjected to saturated steam at 100C. for 3 minutes. There was obtained a blue fabric which ehhibited excellent fastness to sunlight and humidity.

EXAMPLE 3 The procedure of Example 2 was repeated in every essential detail except that in place of saturated steam the fabric was subjected to dry heat at 150C. for 1 minute. There was again obtained a blue fabric of excellent fastness to sunlight and humidity.

l claim:

A process for dyeing acrylic fibers obtained from a long-chain synthetic polymer composed of at least 70 percent acrylonitrile units by weight which comprises treating said fibers with a dyebath consisting essentially of:

a. a basic dyestuff containing a pentavalent nitrogen atom; bv an aromatic ketone of the formula wherein Y is selected from the group consisting of hydrogen, halogen and alkyl of 1-4 carbon atoms and R is alkyl of 14 carbon atoms; and

c. a dye-dissolving agent selected from the group consisting of acetic acid, formic acid, thiosteam is at 100C.

5. The process of claim 3 wherein said dry heat is at [5 150C. 

1. A PROCESS FOR DYEING ACRYLIC FIBERS OBTAINED FROM A LONGCHAIN SYNTHETIC POLYMER COMPOSED OF AT LEAST 70 PERCENT ACRYLONITRILE UNITS BY WEIGHT WHICH COMPRISES TREATING SAID FIBERS WITH A DYEBATH CONSISTING ESSENTIALLY OF: A. A BASIC DYESTUFF CONTAINING A PENTAVALENT NITROGEN ATOM; B. AN AROMATIC KETONE OF THE FORMULA
 2. The process of claim 1 wherein said heat treatment is by means of saturated steam.
 3. The process of claim 1 wherein said heat treatment is by means of dry heat.
 4. The process of claim 2 wherein said saturated steam is at 100*C.
 5. The process of claim 3 wherein said dry heat is at 150*C. 